1. Technical Field of the Invention
This invention relates to radio telecommunication systems, and more particularly, to a method of providing an announcement to a called mobile subscriber indicating that the connection of an incoming call may be delayed.
2. Description of Related Art
In radio telecommunications networks, multiple exchanges may operate together, each exchange being defined as the service area of a mobile switching center (MSC). A mobile subscriber may roam from exchange to exchange, and at any given time, the exchange in which the subscriber is operating is referred to as the serving MSC. An incoming call for the mobile subscriber may originate in an originating MSC and be routed to the serving MSC for delivery to the mobile subscriber.
When an incoming call is received for a mobile subscriber in a radio telecommunication system, a system operator may selectively seize a radio voice channel to the mobile station and alert the mobile subscriber before a voice trunk is established between the originating and serving exchanges. Systems utilizing this alert-and-answer-before-routing feature may experience sigifficant delays between the time that the mobile subscriber is alerted, and the call is delivered. In addition, increased demands on the resources of the cellular system, as well as other commercial services, which use alert-and-answer-before-routing implementation, may lead to unexpected delays in call delivery. As a result, the called party may prematurely terminate the call by hanging up before call delivery is completed, thereby creating a loss of revenue to system operators.
Although there are no known prior art teaching of a solution to the aforementioned deficiency and shortcomings of alerting a called party before establishing a voice trunk U.S. Pat. No. 4,723,273 to Diesel et al (Diesel) discloses subject matter which bears some relation to the matters disclosed herein. Diesel discloses a call forwarding method that allows the called party to selectively forward alerted calls without first establishing a voice channel or requiring the called party to answer the call. This discretionary call forwarding feature utilizes an out-of-band signaling channel to receive and transmit calling party information. Review of Diesel reveals no teaching or suggestion of a system or method such as that disclosed herein for notifying a called party to wait for the delayed connection of an answered incoming call alert.
It would be a distinct advantage to have a method in a radio telecommunication system for notifying a called party to wait for the delayed reception of an incoming call after responding to a call alert, and thereby increase the percentage of completed incoming calls.